NAME

    Export::Attrs - The Perl 6 'is export(...)' trait as a Perl 5 attribute

VERSION

    This document describes Export::Attrs version 0.000005

SYNOPSIS

        package Some::Module;
        use Export::Attrs;
    
        # Export &foo by default, when explicitly requested,
        # or when the ':ALL' export set is requested...
    
        sub foo :Export(:DEFAULT) {
            print "phooo!";
        }
    
    
        # Export &var by default, when explicitly requested,
        # or when the ':bees', ':pubs', or ':ALL' export set is requested...
        # the parens after 'is export' are like the parens of a qw(...)
    
        sub bar :Export(:DEFAULT :bees :pubs) {
            print "baaa!";
        }
    
    
        # Export &baz when explicitly requested
        # or when the ':bees' or ':ALL' export set is requested...
    
        sub baz :Export(:bees) {
            print "baassss!";
        }
    
    
        # Always export &qux
        # (no matter what else is explicitly or implicitly requested)
    
        sub qux :Export(:MANDATORY) {
            print "quuuuuuuuux!";
        }
    
    
        # Allow the constant $PI to be exported when requested...
    
        use Readonly;
        Readonly our $PI :Export => 355/113;
    
    
        # Allow the variable $EPSILON to be always exported...
    
        our $EPSILON :Export( :MANDATORY ) = 0.00001;
    
    
        sub IMPORT {
            # This subroutine is called when the module is used (as usual),
            # but it is called after any export requests have been handled.
        };

DESCRIPTION

    NOTE: This module is a fork of Perl6::Export::Attrs created to restore
    compatibility with Perl6::Export::Attrs version 0.0.3.

    Implements a Perl 5 native version of what the Perl 6 symbol export
    mechanism will look like (with some unavoidable restrictions).

    It's very straightforward:

      * If you want a subroutine or package variable to be capable of being
      exported (when explicitly requested in the use arguments), you mark
      it with the :Export attribute.

      * If you want a subroutine or package variable to be automatically
      exported when the module is used (without specific overriding
      arguments), you mark it with the :Export(:DEFAULT) attribute.

      * If you want a subroutine or package variable to be automatically
      exported when the module is used (even if the user specifies
      overriding arguments), you mark it with the :Export(:MANDATORY)
      attribute.

      * If the subroutine or package variable should also be exported when
      particular export groups are requested, you add the names of those
      export groups to the attribute's argument list.

    That's it.

 IMPORT blocks

    Perl 6 replaces the import subroutine with an IMPORT block. It's
    analogous to a BEGIN or END block, except that it's executed every time
    the corresponding module is use'd.

    The IMPORT block is passed the argument list that was specified on the
    use line that loaded the corresponding module, minus the arguments that
    were used to specify exports.

    Note that, due to limitations in Perl 5, the IMPORT block provided by
    this module must be terminated by a semi-colon, unless it is the last
    statement in the file.

DIAGNOSTICS

    %s does not export: %s\nuse %s failed

      You tried to import the specified subroutine or package variable, but
      the module didn't export it. Often caused by a misspelling, or
      forgetting to add an :Export attribute to the definition of the
      subroutine or variable in question.

    Bad tagset in :Export attribute at %s line %s: [%s]

      You tried to import a collection of items via a tagset, but the
      module didn't export any subroutines under that tagset. Is the tagset
      name misspelled (maybe you forgot the colon?).

    Can't export lexical %s variable at %s

      The module can only export package variables. You applied the :Export
      marker to a non-package variable (almost certainly to a lexical).
      Change the variable's my declarator to an our.

    Can't export anonymous subroutine at %s

      Although you can apply the :Export marker to an anonymous subroutine,
      it rarely makes any sense to do so, since that subroutine can't be
      exported without a name to export it as. Either give the subroutine a
      name, or make sure it's aliased to a named typeglob at compile-time
      (or, at least, before it's exported).

CONFIGURATION AND ENVIRONMENT

    Export::Attrs requires no configuration files or environment variables.

DEPENDENCIES

    This module requires the Attribute::Handlers module to handle the
    attributes.

INCOMPATIBILITIES

    This module cannot be used with the Memoize CPAN module, because
    memoization replaces the original subroutine with a wrapper. Because
    the :Export attribute is applied to the original (not the wrapper), the
    memoized wrapper is not found by the exporter mechanism.

LIMITATIONS

    Note that the module does not support exporting lexical variables,
    since there is no way for the exporter mechanism to determine the name
    of a lexical and hence to export it.

    Nor does this module support the numerous addition export modes that
    Perl 6 offers, such as export-as-lexical or export-as-state.

SUPPORT

 Bugs / Feature Requests

    Please report any bugs or feature requests through the issue tracker at
    https://github.com/powerman/perl-Export-Attrs/issues. You will be
    notified automatically of any progress on your issue.

 Source Code

    This is open source software. The code repository is available for
    public review and contribution under the terms of the license. Feel
    free to fork the repository and submit pull requests.

    https://github.com/powerman/perl-Export-Attrs

        git clone https://github.com/powerman/perl-Export-Attrs.git

 Resources

      * MetaCPAN Search

      https://metacpan.org/search?q=Export-Attrs

      * CPAN Ratings

      http://cpanratings.perl.org/dist/Export-Attrs

      * AnnoCPAN: Annotated CPAN documentation

      http://annocpan.org/dist/Export-Attrs

      * CPAN Testers Matrix

      http://matrix.cpantesters.org/?dist=Export-Attrs

      * CPANTS: A CPAN Testing Service (Kwalitee)

      http://cpants.cpanauthors.org/dist/Export-Attrs

AUTHOR

    Alex Efros <powerman@cpan.org>

    Damian Conway <DCONWAY@cpan.org>

COPYRIGHT AND LICENSE

    This software is Copyright (c) 2016 by Alex Efros <powerman@cpan.org>.

    Copyright (c) 2005,2015 Damian Conway <DCONWAY@cpan.org>. All rights
    reserved.

    This module is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

